1. Field of the Invention
This invention relates to a process for water-washing and drying a semiconductor element whose one side has been subjected to etching, such as a silicon wafer or glass photomask.
2. Description of the Prior Art
When forming a semiconductor-wiring circuit on one surface of a semiconductor element having a thin plate-like shape, a thin metal film or oxide film is applied on the surface of the semiconductor element and a photoresist is coated as a thin film on desired areas of the surface of the element. The photoresist is exposed and then developed to form a pattern which will serve as the wiring circuit. Then, the thus-developed semiconductor element is subjected to etching so as to remove thin metal films at areas other than those where the pattern has been formed. Thereafter, the photoresist is peeled off to give the semiconductor-wiring circuit.
According to the prior art technique, an etched semiconductor element is moved into a water-washing tank by means of a chuck head, where only one surface in which a circuit is to be formed is washed with water. Then, it is placed in a carrier held in a water tank which is generally called a "pool". After the carrier has been filled with a prescribed number of wafers, generally, with 25-50 sheets of wafers, the wafers are transferred still in the carrier to the next drying step. Therefore, semiconductor elements which were placed earlier in the carrier are kept for longer periods of time in the water of the pool. When 25 sheets of semiconductor elements are held in the carrier for example, the semiconductor element which is first placed in the carrier will remain for 72 minutes in the water if each sheet of semiconductor elements takes 3 minutes for its processing. Since a small amount of an etchant is still present on each semiconductor element when it is placed in the pool, the etchant is added to the water in the pool. Ions are formed from the thus-added etchant, thereby subjecting the surface of each semiconductor element to a further reaction. Thus, the prior art process is accompanied by a drawback that the surface of each semiconductor element is changed when it is immersed for a long period of time in water.